He stands by the entrance of a Middle Eastern grocery in khakis and a baseball cap, trying to blend in. He smiles gently. He offers the occasional Arabic greeting.

Quietly, he searches the aisles for a version of himself: an Iraqi expatriate with greater ambition than prospects, a Muslim immigrant willing to fight an American war.

There are countless hard jobs for American soldiers supporting the occupation of Iraq. Few seem more impossible than the one assigned to Sergeant Murad. As the conflict grows increasingly violent and unpopular, the sergeant must persuade native Arabic speakers to enlist and serve with front-line troops.

“I feel like a nomad in the middle of the desert, looking for green pastures,” said Sergeant Murad, 34, who is from the Kurdish region of Iraq.

Linguists have emerged as critical figures in the occupation. They interpret for commanders in meetings with mayors and sheiks. They translate during the interrogation of Iraqi prisoners. They shadow troops on risky missions.

In the pressing search for Arabic speakers, the military has turned to Middle Eastern immigrants in the United States. Sergeant Murad is a rising star in this effort. He has recruited 10 men to the program in little more than a year, a record unrivaled in the Army National Guard.

Still, he is an unlikely foot soldier in the campaign. His own evolution — from a teenage immigrant who landed in North Dakota after the first gulf war to a spit-and-polish sergeant — has been marked with private suffering.

In boot camp, he was called a “raghead.” Comrades have questioned his patriotism. Last year a staff sergeant greeted him by calling out, “Here comes the Taliban!”

He remembers a day in 2002 when the comedian Drew Carey visited a base in Saudi Arabia where he was working. During a skit, Sergeant Murad recalled, Mr. Carey dropped to the ground to mimic the Muslim prayer. As the troops roared with laughter, Sergeant Murad walked out.

“I thought about my mom when she prays, how humble she is,” he said.

Yet, day after day, Sergeant Murad sets out to sell other immigrants on the life he has lived. He believes that Muslims need the military more than ever, he said: At a time when many feel alienated, it offers them a path to assimilation, a way to become undeniably American.

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Feeling Like an Outcast

The sergeant is six feet tall, but often stands shrunken, his hands politely clasped. He has a long, distinguished nose and wears glasses that darken in the sun but never fully fade, lending him a distant aura.

He plies the streets of El Cajon in a rumbling, black Toyota Tacoma pickup. In the back, he carries stacks of fliers advertising what the Army calls the “09-Lima” program.

Through the program, speakers of Arabic, Farsi, Dari, Pashto and Kurdish are sent to boot camp like other soldiers. They later receive specialized training as linguists, and a majority are deployed to Iraq.

Of the thousands of interpreters working for the military in Iraq, most are civilians under contract, some of whom earn as much as $170,000 a year. But military commanders prefer uniformed linguists because they cannot refuse combat missions and are subjected to more thorough security checks.

They are offered a fraction of what many civilian linguists earn, with salaries starting at roughly $28,000, including allowances. The program’s perks, such as expedited citizenship, a starting bonus and medical coverage, are a major draw, military officials said.

Since the Army created the program in 2003, more than 800 people have signed up. But nearly 40 percent of them have either dropped out or failed language tests or boot camp. Enlistment in the program has improved with the help of civilian Arabic speakers contracted by the Army to recruit.

In California, the Army National Guard is trying the same approach, but with troops. Capt. Hatem Abdine assembled a team of soldiers of mostly Middle Eastern descent to help recruit full time, and brought Sergeant Murad on board last year.

In April, the sergeant arrived in El Cajon. Before his first week was up, he felt like an outcast.

Stacks of fliers and business cards that he had left in grocery stores had vanished. Cashiers who welcomed him on his first visits were suddenly too busy to talk. One manager fled the store. The owner of another shop turned his back and flipped kebobs over a high-licking flame.

“They’re so agitated when I approach them,” Sergeant Murad said. “Is it because I’m ugly? I don’t think I’m that ugly.”

Nestled in a parched valley, El Cajon drew its first Iraqi settlers half a century ago because of the resemblance it bore to their homeland. The population boomed in the 1990’s when thousands of refugees — primarily Kurds and Shiites — joined what had long been the domain of whites and Hispanics.

Sergeant Murad makes his rounds with a truck full of Army promotional items, including a box of T-shirts that state, in Arabic, “If you can read this” — and then in English — “the National Guard needs you.” He cannot bring himself to wear one.

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Last April, Sergeant Murad drove to a boxy stucco house to visit the pregnant wife of a 22-year-old Shiite recruit. The woman was worried about her husband’s safety in Iraq.

“The fact that he’s an Iraqi — it’s unfathomable to these nationals that he would be with the United States military,” she said in Arabic, perched on a couch next to her mother-in-law.

“He is Muslim and in the military — it doesn’t look right.”

The older woman frowned.

“If it were up to me, I would make you join the military because they freed you from Saddam,” she told her daughter-in-law.

Boot camp had been effective, the mother said. Her son seemed newly disciplined, more mature. There was only one thing she disliked: his limited vacation.

“Just two weeks!” she said. “Even in the army of Saddam Hussein, this wasn’t the case.”

On a sunny afternoon in August, Sergeant Murad was back in his truck, cruising El Cajon with a fresh stack of business cards.

He was learning to avoid certain shops. He waved mockingly at the kebab store as his truck rolled by, no longer concerned about who might be watching.

He had come to the conclusion that first impressions counted little.

Plenty of Iraqis had misjudged him. Eventually, though, they grew to like him.

It was the same with soldiers, Sergeant Murad said. He looked back on his time in boot camp as the ultimate proof that hardship can be overcome, and wary comrades, won over.

“In the end, when somebody gets to know Cam the soldier, Cam the citizen, they always take my side,” he said. “That’s where my triumph is. The hurt goes away.”